Method and apparatus for preventing strip accumulation

ABSTRACT

Apparatus for preventing accumulation of strip between stands of a multistand hot or cold reduction mill when a strip breaks includes a curved knife blade of greater width than the strip, means for maintaining the knife in a stand-by position above the path of the strip, and means for moving the knife into contact with the strip to cut and reverse the direction of travel of the strip. The method consists of detecting the strip break, actuating a cutting means, cutting the strip and reversing the direction of strip travel.

United States Patent Koss et a1. Oct. 14, 1975 [54] METHOD AND APPARATUS FOR 3,552,161 1/1971 Garbe et 211.. 72/4 PREVENTING STRIP ACCUMULATION 3,741,054 6/1973 Alperin et a1 83/106 Inventors: George S. Koss, Birmingham; Jay R. Scott, Mountain Brook, both of Ala.

United States Steel Corporation, Pittsburgh, Pa.

Filed: Mar. 28, 1974 Appl. No.: 455,689

Related US. Application Data Division of Ser. No. 288,621, Sept. 13, 1972, Pat. No. 3,826,415.

Assignee:

US. Cl 72/203; 72/230 Int. Cl? B21B 39/00 Field of Search 72/4, 5, 3, 1, 203, 230;

References Cited UNITED STATES PATENTS 2/1962 Peters 72/234 X Primary ExaminerMilton S. Mehr ABSTRACT Apparatus for preventing accumulation of strip between stands of a multistand hot or cold reduction mill when astrip breaks includes a curved knife blade of greater width than the strip, means for maintaining the knife in a stand-by position above the path of the strip, and means for moving the knife into contact with the strip to cut and reverse the direction of travel of the strip. The method consists of detecting the strip break, actuating a cutting means, cutting the strip and reversing the direction of strip travel,

3 Claims, 1 Drawing Figure US. Patent Oct. 14, 1975 METHOD AND APPARATUS FOR PREVENTING STRIP ACCUMULATION This is a division of application Ser. No. 288,621, filed Sept. 13, 1972 (now U.S. Pat. No. 3,826,415).

This invention relates primarily to an apparatus to be used in combination with a multistand high speed re-' duction mill for cutting moving strip and preventing its entry into the first stand of the mill. Hot strip mills normally consist of a roughing mill followed by from 3 to 6 finishing stands. When six stands are used, the speed of the product leaving the last stand of the mill is often in excess of 2,000 feet per minute. A cold reduction mill usually has about the same number of stands as a hot reduction mill. The product leaving the last stand of a cold mill can be traveling in excess of 7,000 feet per minute. Normally, whenever a strip breaks or a cobble occurs between stands, there is a long deceleration period during which the strip continues to be fed into the reduction mill by all stands preceding the strip break or'cobble. This causes the stip to pile up between the mill stands which not only can cause damage to the equipment, but also is extremely time consuming to remove. Occasionally, a broken strip will wrap around the work roll and wreck the mill. Rolls must then be changed resulting in further downtime before the mill can resume production.

The primary object of our invention is to provide an apparatus in combination with a high speed strip mill that will prevent strip from entering the first stand of a multistand mill when a break or cobble occurs in the mill.

lt is also an object of our invention to provide an apparatus for use in combination with a high speed strip mill that will prevent accumulation of strip near the entry side of any roll stand of a multistand mill including the first stand.

It is another object of our invention to provide an apparatus that is simple and economical to use and easy to maintain.

Another object of our invention is to provide an apparatus for use in combination with a high speed strip mill that will sever the strip being fed into the mill mo mentarily upon the occurrence of a break or cobble.

A further object of our invention is to provide a method of preventing strip entry into a high speed strip mill on occurrence of a strip break or cobble.

We have invented a strip severing apparatus which is positioned before the first stand of a multistand strip mill above the path of travel of the strip. The apparatus includes a curved blade which drops downwardly against the strip to thereby cut the strip and change its direction of travel back upon itself.

Our invention is better understood by reference to the following detailed description and the appended drawing in which:

The single FIGURE is an isometric view of the preferred embodiment of our invented strip cutting apparatus.

Considering now the invention in some detail, and referring to the illustrated form thereof in the drawing, our strip cutting apparatus is mounted between a feed roll 10 and the first stand of a multistand reduction mill, the stand being represented by work rolls [2 and 6 shown in the drawing, hasa horizontal cutting edge 22 and a wedge-shaped central piercing protrusion 24 near the-center of its lower edgeJA strip guide 26, which may be a plate, is mounted between thefeed roll 10 and bottom work roll 12.:The guide has a hole 27 therein to receive piercing protrusion 24. A double acting-air cylinder 30 is mounted atop the frame 20 and anchored thereto. Piston rod 32 extending from the air cylinder is fastened to knife blade 14 by a clevis 34 and pin 35. The pneumatic cylinder is actuated by means of a solenoid-operated pneumatic valve 40.

In operation, the knife blade 14 is held in the ready or stand-by position above the path of strip S by air cylinder 30 which holds piston rod 32 in the retracted position. In the event of a strip break or cobble at the entry side of any of the reducing stands in the mill, valve 40 is actuated to cause the piston rod to extend. This may be accomplished manually or a strip detector may be used to automatically actuate the pneumatic cylinder. This causes the knife blade 14 to pivot about its shaft 16, moving its lead edge 22 downwardly at a rapid rate, forcing the wedge-shaped central piercing protrusion 24 into and through the center of the moving strip S and into hole 27 in strip guide 26, shearing the strip outwardly from its center. The strip follows the curvature of the knife blade and moves back over itself into an areain front of the reducing mill, that is, to the left of feed roll 10 as shown in the drawing. This area is easily accessible for cleanup and is not subject to damage from strip pile up because there is little or no operating equipment in this area.

It has been found that the knife blade 14 does not always rupture the strip unless the wedge-shaped protrusion 24 is present. This imparts a tearing action to the strip which is completed as the cutting edge 22 of the knife hits the strip across its full width.

Although a highly detailed embodiment of the invention has been shown and described above, it is obvious that many modifications can be made without departing from the spirit of the invention. For example, the knife blade could be straight and could drop vertically. The function of the curved portion of the blade could be performed by a curved guide between the blade and the first work roll stand which would be contacted by the strip after being cut, and thereupon change the direction of strip travel back upon itself because of the curvature of the guide. The knife blade could be pivoted at one side of the frame 20 in such a manner that it would contact one edge of the strip first. The knife could be held in a stand-by position by an electromagnet. In this case, the power could be switched off to drop the blade into the cutting position.

It is readily apparent from the foregoing that we have invented a strip cutting device which will rapidly cut a moving strip and change its direction of travel to prevent it from piling up near the entry side of work rolls in a multistand reducing mill whenever the strip breaks or a cobble occurs.

We claim:

1. In combination with a high speed multistand strip mill having a pair of work rolls in each stand, apparatus for cutting a strip traveling through said mill, said apparatus comprising:

a frame;

a curved knife blade having a width greater than that of said strip, said knife blade being journaled for rotation upon said frame;

wardly from the lower edge of said blade.

3. Apparatus according to claim 2 further comprising a strip guide positioned at the entry side of said reducing mill beneath the path of travel of said strip, said strip guide being provided with a hole for receiving said protrusion of said blade. 

1. In combination with a high speed multistand strip mill having a pair of work rolls in each stand, apparatus for cutting a strip traveling through said mill, said apparatus comprising: a frame; a curved knife blade having a width greater than that of said strip, said knife blade being journaled for rotation upon said frame; means for maintaining said knife blade in a stand-by position above the path of travel of said strip, and means for moving said knife blade Into contact with said strip, said knife blade acting as a guide for reversing the direction of travel of said strip.
 2. A combination according to claim 1 further comprising a wedgeshaped protrusion extending downwardly from the lower edge of said blade.
 3. Apparatus according to claim 2 further comprising a strip guide positioned at the entry side of said reducing mill beneath the path of travel of said strip, said strip guide being provided with a hole for receiving said protrusion of said blade. 